Virgin Blue thought it was the work of a disgruntled worker

Police said that the firework fell out of the boy's luggage and into the hold of an airliner, where it was found by a Sydney airport worker on Monday.

Virgin Blue said at the time that a disgruntled worker may have planted it.

The incident was the latest in a string of security scares for Australian aviation and came ahead of a general election where security is a big issue.

A baggage handler found the device on Monday in the cargo hold of a Virgin Blue Boeing 737 airliner when it landed in Sydney after an internal flight from the state of Queensland.

Police are satisfied that this firecracker posed no threat to the aircraft and there was no malicious intent Australian Federal Police

He then breached security procedures by carrying it into the terminal.

"AFP [Australian Federal Police] officers interviewed a young teenager who identified the suspect item as a homemade firecracker that he was carrying in his luggage on the flight from Maroochydore to Sydney," said a police spokeswoman.

"Police are satisfied that this firecracker posed no threat to the aircraft and there was no malicious intent.

"The AFP will not be taking any action... he's not going to be charged."

In July, a flight bound for Los Angeles was forced to return to Sydney when flight staff discovered the letters "BOB" - interpreted as possibly meaning "bomb on board" - scrawled on a sick bag in an aircraft toilet

It later transpired that "BOB" can also denote "Best on board" - a term used by air crew to identify good-looking passengers.